Hi All,
I've been looking at using a relay to switch a 240VAC circuit. I've noticed that the vast majority of these relays are specified, and certified, at 250VAC for the maximum current rating.
If you assume the UK mains is 240VAC +6%/-10% (shortly to become harmonised to 230VAC +/-10%), this would mean that at worst case the voltage could be 240VAC + 6%, i.e. 254.4VAC. This would preclude the vast majority of these relays from ever being used on UK mains (or anywhere that uses 230VAC +/-10%)!!
Now, let's say the relay current is significantly over-rated, e.g. switching 16A with a 30A rated relay. Would that be an argument to allow the extra 4.4VAC and allow the component to be used? Does the certification allow, or justify, such derating?
It seems crazy to me that they certify these components to 250VAC rather than 254VAC. Any thoughts anyone?
I've been looking at using a relay to switch a 240VAC circuit. I've noticed that the vast majority of these relays are specified, and certified, at 250VAC for the maximum current rating.
If you assume the UK mains is 240VAC +6%/-10% (shortly to become harmonised to 230VAC +/-10%), this would mean that at worst case the voltage could be 240VAC + 6%, i.e. 254.4VAC. This would preclude the vast majority of these relays from ever being used on UK mains (or anywhere that uses 230VAC +/-10%)!!
Now, let's say the relay current is significantly over-rated, e.g. switching 16A with a 30A rated relay. Would that be an argument to allow the extra 4.4VAC and allow the component to be used? Does the certification allow, or justify, such derating?
It seems crazy to me that they certify these components to 250VAC rather than 254VAC. Any thoughts anyone?